具有自由边界的吹吸气流的数值解法(英文)

本文旨次论述了具有自由边界的二维层流或湍流吹吸气流的数值计算方法。本文将具有速度梯度和气体能自由进出同一开口面上的边界称为“自由边界”。借助于自由边界的帮助可方便地确立出吹出气流和吸入气流流量的最佳组合即能方便地求出最小流量比。通过气流显示实验验证,本文提出的计算方法是十分成功和有效的。     

浅谈冲孔桩的施工工艺流程及施工方法

冲孔桩是目前广东高架桥梁及大型建筑物桩基础常采用主要形式之一，它适用于穿越粘性土、砂土、碎(砾)石及风化层，包括地质情况比较复杂，夹层多，风化不均匀，软硬变化较大的岩层。这里浅谈广州(新)白云机场旅客过夜用房基础施工工艺流程和施工方法。     

钛合金TC11深孔钻削刀片材料的选择

在研究了钛舍金材料切削性能的基础上，针对钛合金的特点，选用了五种国内常用的硬质舍金刀片材料，对钛合金进行深孔钻削刀具磨损试验。结果表明，确定了适合钻削钛合金TC11的硬质合金刀片材料。     

用信息化建设推动集团公司的快速发展

航空制造业是应用信息技术最早和最有成效的产业之一，在这方面，虽然我国航空工业已经拥有了一定的基础，但总体的信息化建设还处于“初级阶段”。今后的五年，将是航空工业一集团信息化建设最为重要的时期，他们已经计划并开始实施     

“一代师表”徐特立的高尚品德与教育历程

徐特立(1877-1968),中国无产阶级革命家、教育家。徐特立原名懋恂,字师陶,又名立华,出生在湖南长沙一个贫苦农民家里。他从小家里很穷,四岁丧母,父兄种田,终年劳作,一家仍不得温饱。为了不使孩子     

Why Raman spectroscopy on Mars?--a case of the right tool for the right job

We provide a scientific rationale for the astrobiological investigation of Mars. We suggest that, given practical constraints, the most promising locations for the search for former life on Mars are palaeolake craters and the evaporite deposits that may reside within them. We suggest that Raman spectroscopy offers a promising tool for the detection of evidence of former (or extant) biota on Mars. In particular, we highlight the detection of hopanoids as long-lived bacterial cell wall products and photosynthetic pigments as the most promising targets. We further suggest that Raman spectroscopy as a fibre optic-based instrument lends itself to flexible planetary deployment.     

Influence of ionic inorganic solutes on self-assembly and polymerization processes related to early forms of life: implications for a prebiotic aqueous medium

A commonly accepted view is that life began in a marine environment, which would imply the presence of inorganic ions such as Na+, Cl-, Mg2+, Ca2+, and Fe2+. We have investigated two processes relevant to the origin of life--membrane self-assembly and RNA polymerization--and established that both are adversely affected by ionic solute concentrations much lower than those of contemporary oceans. In particular, monocarboxylic acid vesicles, which are plausible models of primitive membrane systems, are completely disrupted by low concentrations of divalent cations, such as magnesium and calcium, and by high sodium chloride concentrations as well. Similarly, a nonenzymatic, nontemplated polymerization of activated RNA monomers in ice/eutectic phases (in a solution of low initial ionic strength) yields oligomers with > 80% of the original monomers incorporated, but polymerization in initially higher ionic strength aqueous solutions is markedly inhibited. These observations suggest that cellular life may not have begun in a marine environment because the abundance of ionic inorganic solutes would have significantly inhibited the chemical and physical processes that lead to self-assembly of more complex molecular systems.     

Eye light flashes on the Mir space station

The phenomenon of light flashes (LF) in eyes for people in space has been investigated onboard Mir. Data on particles hitting the eye have been collected with the SilEye detectors, and correlated with human observations. It is found that a nucleus in the radiation environment of Mir has roughly a 1% probability to cause an LF, whereas the proton probability is almost three orders of magnitude less. As a function of LET, the LF probability increases above 10 keV/micrometer, reaching about 5% at around 50 keV/micrometer.     

MEDES clinical research facility as a tool to prepare ISSA space flights

This new multi-disciplinary medical experimentation center provides the ideal scientific, medical and technical environment required for research programs and to prepare international space station Alpha (ISSA) missions, where space and healthcare industries can share their expertise. Different models are available to simulate space flight effects (bed-rest, confinement,...). This is of particular interest for research in Human psychology, physiology, physiopathology and ergonomics, validation of biomedical materials and procedures, testing of drugs, and other healthcare related products. This clinical research facility (CRF) provides valuable services in various fields of Human research requiring healthy volunteers. CRF is widely accessible to national and international, scientific, medical and industrial organisations. Furthermore, users have at their disposal the multi-disciplinary skills of MEDES staff and all MEDES partners on a single site.